The invention relates to a method for transporting and inspecting semiconductor substrates. In addition, the invention relates to an arrangement for transporting and inspecting semiconductor substrates.
U.S. Pat. No. 5,863,170 discloses a modular process system for semiconductors. This system, for handling wafers, is of modular construction and has a large number of process stations, which are loaded with wafers. The wafers are forwarded from process station to process station by a central carousel. In the process stations, various process steps are carried out on the wafers. This arrangement can be used only for treatment in various process stations. Monitoring and inspection of the wafers is not provided.
U.S. Pat. No. 5,807,062 discloses an arrangement for handling wafer-like objects. The wafers in the arrangement are transferred from and to magazines. In the arrangement itself there are arranged three workstations. In the first workstation, the wafer-like object is aligned with respect to a plane and an angle. The next workstation represents the x/y table of an inspection microscope. The third workstation is used for the visual monitoring of the wafer-like objects by an operator. The workstations are in each case arranged at an angle of 120xc2x0 to one another. A changer sits between the workstations and, with its three arms, can feed the wafer-like objects to the individual workstations. The changer has three arms and additional means for the fine positioning of the wafer-like objects.
To this end, there is on the shaft of the changer a gearwheel, in which jaws with identical toothing engage and thus permit fine adjustment of the changer. The drawback with this arrangement is that it cannot be used so universally, and fine positioning takes up a relatively long time.
It is the object of the present invention to provide a method with which wafer-like objects can be handled in a time-saving manner, and a high throughput of the wafer-like objects is achievable with this method.
The object is achieved by a method comprising the steps of:
providing at least three workstations arranged in a housing, wherein a changer being arranged in such a way that each of the workstations can be supplied with a semiconductor substrate;
lifting the changer and carrying out a rotational movement by a specific angular amount, in order to transfer al least one of the semiconductor substrates to another workstation;
lowering the changer and carrying out a rotational movement by the same angular amount in the opposite direction, without a semiconductor substrate resting on the changer; and
picking up a new semiconductor substrate from a substrate feed module.
It is a further object of the invention to provide an arrangement which permits wafer-like objects to be inspected visually and microscopically in a simple, time-saving manner. Added to this is the intention that the arrangement shall also be able to operate with inaccurately positioned wafer-like objects. Furthermore, wafer-like objects of different sizes are intended also to be processed with the invention.
The object is achieved by an arrangement for transporting and inspecting semiconductor substrates which comprises at least three workstations, a changer defining an axis of rotation, wherein the changer has at least three arms, and which is designed to load the at least three workstations with semiconductor substrates, the workstations being arranged coaxially around the axis of rotation of the changer, a measuring device is assigned to one workstation, wherein the measuring device determines the deviation of the current position of the semiconductor substrate from an intended position and makes it available to the arrangement for the further inspection of the semiconductor substrate and in that the changer is not equipped with means for moving the semiconductor substrates into the intended position.
It is advantageous to have an arrangement for transporting and inspecting semiconductor substrates. The arrangement comprises:
a first, second and third workstation,
a changer defining an axis of rotation, wherein the changer has three arms, and which is designed to load and unload the three workstations with semiconductor substrates,
the first workstation defines a transfer position, at which semiconductor substrates are introduced into the arrangement from a substrate feed module and can be transferred from the arrangement to the substrate feed module,
the second workstation is a measuring device, which determines the deviation of the current position of the semiconductor substrate from an intended position and makes it available to the arrangement for the further inspection of the semiconductor substrate, and
the third workstation defines a micro inspection and comprises an x/y table, which feeds the semiconductor substrate to a microscope.